Question

A person going for a morning jog on the deck of a cruise ship is running toward the bow (front) of the ship at 2.0 m s while the ship is moving ahead at 8.5 m s. What is the velocity of the jogger relative to the water? Later, the jogger is moving toward the stern (rear) of the ship. What is the jogger’s velocity relative to the water now?

Answer 1

1)

velocity of person with respect to ship,

vps = 2.0 x (taking forward as positive x direction)

velocity of ship with respect to water,

vsw = 8.5 x (taking forward as positive x direction)

so,

vpw = vps + vsw

= 2.0 + 8.5

= 10.5 x

Answer: 10.5 m/s

2)

velocity of person with respect to ship,

vps = - 2.0 x (taking forward as positive x direction)

velocity of ship with respect to water,

vsw = 8.5 x (taking forward as positive x direction)

so,

vpw = vps + vsw

= - 2.0 + 8.5

= 6.5 x

Answer: 6.5 m/s